(1) Field of the Invention
This invention relates to a process for the preparation of a titanium-based catalyst component (hereinafter referred to simply as a catalyst component) of a catalyst for use in the polymerization of olefins composed of the titanium-based catalyst component and an organo aluminium compound, where polymerization includes homopolymerization and copolymerization thereof.
That is, this invention relates to a process for the preparation of a catalyst component having such a high activity that when applied to the polymerization of olefins it serves to show a high activity, and stereoregular polymer can be obtained in high yield, and more particularly relates to a process for the preparation of a catalyst component, which comprises contacting a fatty acid salt of magnesium, an electron donor compound and a titanium halide of the general formula: TiX.sub.4, wherein X represents a halogen atom.
(2) Description of the Prior Art
A titanium halide is well known in the art as a catalyst component for use in the polymerization of olefins. However, in the polymerization with the titanium halide known as the conventional catalyst component, the yield of polymer per unit weight of the catalyst component or of titanium moiety in the catalyst component (hereinafter referred to simply as a polymerization activity per unit weight of the catalyst component or of titanium) is so low that the so-called deashing process for subsequently removing catalyst residues from the produced polymer is indispensable in order to obtain an industrially applicable polymer. In the deashing process, alcohols or chelating agents are used in large amounts, so that the deashing process needs an apparatus for recovery thereof as well as the deashing apparatus itself, and consequently has many problems accompanying therewith relative to resources, energy, and the like. Thus, the deashing process raises great problems to be solved urgently in the art. A number of studies and suggestions have been made for enhancing the polymerization activity per unit weight of titanium in the catalyst component, so that the complicated deashing process may be dispensed with.
Especially as a recent tendency, a large number of suggestions have been made such that the polymerization activity per unit weight of titanium in the catalyst component is remarkably enhanced in the polymerization of olefins with a catalyst component prepared by supporting a transition-metal compound as an active ingredient such as a titanium halide on a carrier material so that the active ingredient may act effectively.
Japanese Patent Laid-open Publication No. 126590/'75, for example, discloses a process for the preparation of a catalyst component, in which a magnesium halide as a carrier is brought into contact with an aromatic carboxylic acid ester by a mechanical means to form a solid reaction product, and the solid reaction product thus obtained is brought into contact with titanium tetrachloride in the liquid phase to obtain the catalyst component.
However, the prior art employing magnesium chloride as the carrier as described above, has such a disadvantage that the chlorine moiety contained in the magnesium chloride conventionally used as the carrier has an adverse effect on the produced polymer, resulting in leaving problems to be solved such as requirements for such a high activity as to be substantially free from the adverse effect due to the chlorine moiety, or as requirements for controlling a concentration of the magnesium chloride itself at a sufficiently low level.
Thus, attempts have been made on the use of other substances effective as a carrier than magnesium chloride. No attempts as above, however, have succeeded in providing such a process as to be satisfactory for requirements in the art where both high polymerization activity per unit weight of the catalyst component and high yield of stereoregular polymer are needed.
As an example of the above attempts, Japanese Patent Laid-open Publication No. 120980/'74 discloses a process for the preparation of catalyst component for the polymerization of olefins, which comprises reacting magnesium acetate with an aluminium compound to form a reaction product followed by contacting the reaction product with a titanium tetrahalide to obtain a catalyst component, resulting in being unsuitable particularly for the polymerization of propylene, in which high yield of stereoregular polymer is required, and to which this invention is directed, as shown in a comparative example hereinafter illustrated.